Nanoelectromechanical devices for sensing applications

Resonant nanoelectromechanical systems (NEMS) are promising devices for a new class of ultrafast, highly sensitive devices. In this work, fabrication, operation, as well as sensing properties of ceramic wide band gap (AlN and SiC) NEMS sensors will be demonstrated. The internal strain of such beams can be used to improve the resonant performance of the devices. Special attention is drawn to the operation of such sensors in air, which represents a viscous medium and reduces drastically the quality factor of NEMS resonators from 104 to 105 in vacuum to 10–300 in air. This intrinsic property limits the sensitivity for applications in air and has to be taken into account in the design of the sensors. For such resonators, the main problems for an operation in viscous media will be discussed in more detail, and the sensing properties for mass loading, temperature and pressure are exemplarily demonstrated.